Method for preparing resin particles, resin particles and apparatus for preparing resin particles

ABSTRACT

The present provides a method for preparing resin fine particles of a homogeneous particle size used in the fields of chemistry, medicine, electronic material or the like, resin fine particles, and a production apparatus for resin fine particles.  
     The present invention provides a method for preparing a resin fine particle, which comprises discharging a liquid comprising a polymerizable monomer as a dispersion phase into a continuous phase; splitting the liquid comprising the polymerizable monomer by applying mechanical vibration to form a liquid droplet; and polymerizing the liquid droplet in a state without splitting or integrating the liquid droplet, said method comprising recognizing a state of said liquid being split into a liquid droplet, and a condition of said discharging and/or said mechanical vibration of the liquid being determined by feedback from a result of the recognition.

TECHNICAL FIELD

[0001] The present invention relates to a method for preparing resinfine particles of a homogeneous particle size used in the fields ofchemistry, medicine, electronic material or the like, resin fineparticles and a production apparatus for resin fine particles.

BACKGROUND ART

[0002] Conventionally, as a method for producing resin fine particles, asuspension polymerization method is known. This method is a method forplacing a water based medium with a dispersion stabilizer dissolved in areaction vessel with an agitator, introducing a polymerizable monomerwith a polymerization initiator dissolved while agitating, and heating,thereby obtaining resin fine particles. However, the particle sizedistribution of the resin fine particles obtained by the method is wide,so that a sorting operation such as classification is necessary for theapplication requiring the homogeneity of the particle size of a columnfilling material, a spacer, a toner, a material for a foamed product, orthe like, and thus it is extremely complicated.

[0003] In contrast, Japanese Kokai Publication Sho-57-102905 discloses amethod for crushing a polymerizable monomer flow having a laminar flowcharacteristic to small liquid droplets by applying mechanicalvibration, moving the same to a polymerization vessel in a continuousphase, and polymerizing by heating. However, according to the apparatusdisclosed in this method, since a plurality of polymerizable monomeropenings are provided, it is actually difficult to discharge by the sameflow amount from each of the openings, so that the flow amountirregularity is occurred. Thus, the liquid droplets split at the samemechanical frequency has irregularity in capacity, that is, in size.Therefore, according to the apparatus, since the split state cannot begrasped sufficiently, in the case where split failure is occurred, it isdifficult to avoid the split failure so that the particle sizehomogeneity of the final resin fine particles is deteriorated. Moreover,since the apparatus has no mechanism for checking the liquid dropletproduction state or the liquid droplet particle size, even in the casewhere the particle size homogeneity is deteriorated by the productioncondition fluctuation or the like, the production is continued as it is,and thus there is a problem that the homogeneity of the resin fineparticles to be obtained is poor.

SUMMARY OF THE INVENTION

[0004] An object of the present invention is to provide a method forpreparing resin fine particles of a homogeneous particle size used inthe fields of chemistry, medicine, electronic material or the like,resin fine particles, and a production apparatus for resin fineparticles.

[0005] The present invention provides a method for preparing a resinfine particle, which comprises discharging a liquid comprising apolymerizable monomer as a dispersion phase into a continuous phase;splitting the liquid comprising the polymerizable monomer by applyingmechanical vibration to form a liquid droplet; and polymerizing theliquid droplet in a state without splitting or integrating the liquiddroplet, said method comprising recognizing a state of said liquid beingsplit into a liquid droplet, and a condition of said discharging and/orsaid mechanical vibration of the liquid being determined by feedbackfrom a result of the recognition.

[0006] Moreover, the present invention provides a method for preparing aresin fine particle, which comprises discharging a liquid comprising apolymerizable monomer as a dispersion phase into a continuous phase;splitting the liquid comprising the polymerizable monomer by applyingmechanical vibration to form a liquid droplet; and polymerizing theliquid droplet in a state without splitting or integrating the liquiddroplet, said method comprising measuring size of said formed liquiddroplet, and a condition of said discharging and/or said mechanicalvibration of the liquid being determined by feedback from a result ofthe measurement.

[0007] According to one aspect of the present invention, provided is aresin fine particle produced by the method for preparing a resin fineparticle according to the present invention, which has an averageparticle size of 10 to 3,000 μm, and 80% or more of which falls within arange of ±10% of the average particle size.

[0008] According to another aspect of the present invention, provided isa production apparatus for a resin fine particle, which comprises adispersion container; a jetting opening, opened in the dispersioncontainer, for discharging a liquid comprising a polymerizable monomerinto a liquid dispersion medium; a means for applying mechanicalvibration to the liquid comprising the polymerizable monomer jetted intothe liquid dispersion medium; and a photography unit for photographing aformed liquid droplet.

[0009] According to still another aspect of the present invention,provided is a production apparatus for a resin fine particle, whichcomprises a dispersion container; a jetting opening, opened in thedispersion container, for discharging a liquid comprising apolymerizable monomer into a liquid dispersion medium; a means forapplying mechanical vibration to the liquid comprising the polymerizablemonomer jetted into the liquid dispersion medium; and a measuring meansfor measuring size of a formed liquid droplet. Preferably, theproduction apparatus for resin fine particles comprises a means foradjusting a discharging condition and/or a mechanical vibrationcondition of a liquid comprising a polymerizable monomer based on ameasurement result of size of a liquid droplet.

BRIEF DESCRIPTION OF THE DRAWING(S)

[0010]FIG. 1 is a schematic diagram showing a case where liquid dropletsare normally formed from a liquid column of a polymerizable monomer.

[0011]FIG. 2 is a schematic diagram showing a case where no liquiddroplet is formed from a liquid column of a polymerizable monomer due topoor constriction.

[0012]FIG. 3 is a conceptual diagram showing a production apparatus forresin fine particles used in Example 1.

[0013]FIG. 4 is a conceptual diagram showing a production apparatus forresin fine particles used in Example 2.

[0014] In the figures, 1 represents a container for a liquidpolymerizable monomer; 2 represents a jetting opening; 3 represents adispersion container; 4 represents a transducer; 5 represents aphotography unit; 6 represents an illumination unit; 7 represents a CRTdisplay; A represents an amplifier; C1 represents a pump controller; C2represents an image controller; D represents liquid dispersion medium;FG represents a function generator (electrical signal generator); Mrepresents liquid polymerizable monomer; P represents a pump; and Srepresents a measuring unit.

DETAILED DISCLOSURE OF THE INVENTION

[0015] Hereinafter, the present invention will be described in detail.

[0016] A method for preparing a resin fine particle according to thepresent invention comprises discharging a liquid comprising apolymerizable monomer as a dispersion phase into a continuous phase;splitting the liquid comprising the polymerizable monomer by applyingmechanical vibration to form a liquid droplet; and polymerizing theliquid droplet in a state without splitting or integrating the liquiddroplet.

[0017] The continuous phase is not limited to the gas and the liquid.Examples of the gas include air, inert gas such as nitrogen and argon,and the like. Examples of the liquid, in the case of an oil in waterphase system having the continuous phase as a water system and thepolymerizable monomer as an oil system, include water, a solvent mixtureof water and a water soluble organic solvent such as alcohol, and thelike. Moreover, examples of the liquid, in the case of a water in oilphase system having the continuous phase as an oil system and thepolymerizable monomer as a water system, include aliphatic hydrocarbonsuch as n-hexane and n-octane; halide hydrocarbon system such as carbontetrachloride; and aromatic hydrocarbon such as toluene and xylene, andthe like.

[0018] To the continuous phase, it is preferable to add a dispersionstabilizer so as to prevent split and integration of the formed liquiddroplets. The dispersion stabilizer is not particularly limited, andexamples thereof, in the case of an oil in water phase system, includepolyvinyl alcohol; cellulose such as carboxy methyl cellulose andhydroxy methyl cellulose; water soluble polymer such as starch andgelatin; hardly water soluble inorganic salt such as tricalciumphosphate, and the like. In the case of a water in oil phase system,examples of the dispersion stabilizer include sodium alkyl benzenesulfonate and the like.

[0019] To the continuous phase, furthermore, a surfactant, a specificgravity adjusting agent or the like may be added for adjusting thesurface tension.

[0020] As the dispersion phase, a liquid comprising polymerizablemonomer is used. Examples of the polymerizable monomer, in the case ofan oil in water phase system, include a monovinyl aromatic compound suchas styrene, vinyl naphthalene and alkyl substituted styrene; halosubstituted styrene such as bromo styrene and chloro styrene; polyvinylaromatic compound such as divinyl benzene, divinyl toluene, divinylxylene, divinyl naphthalene, trivinyl benzene, divinyl diphenyl etherand divinyl diphenyl sulfone; halo olefin or vinyl halide of vinylchloride or the like; ester of α-β-ethylenically unsaturated carboxylicacid such as ester of acrylic acid or methacrylic acid; methylmethacrylate, ethyl acrylate, vinyl acetate and the like. In particular,in the case of use for the electronic material field, divinyl benzene ascrosslinkable polymerizable monomer capable of obtaining the heatresistance and one produced by mixing divinyl benzene and polyfunctionalacrylate are preferable. These polymerizable monomers may be used aloneor in a combination of two or more kinds.

[0021] Moreover, examples of the polymerizable monomer, in the case of awater in oil phase system, include ethylenically unsaturated carboxyamide such as acrylic amide, methacrylic amide, fumaric amide andethacrylic amide; amino alkyl ester of unsaturated carboxylic acid; acidunhydride; water soluble polymerizable monomer such as ethylenicallyunsaturated carboxylic acid such as acrylic acid and methacrylic acid,and the like.

[0022] To the dispersion phase, a polymerization initiator may be added.As the polymerization initiator, those conventionally known can be used.Examples of the polymerization initiator, in the case of an oil in waterphase system, include benzoyl peroxide, lauroyl peroxide, methyl ethylketone peroxide, potassium persulfate, azo bisisobutylonitrile, azobisvaleronitrile and the like, and in the case of a water in oil phasesystem, include water soluble polymerization initiator such aspersulfate, hydrogen-peroxide and hydroperoxide. Moreover, in the caseof the polymerization by a light beam, a photo polymerization initiatoris used, and other polymerization auxiliary agents such as a chaintransfer agent may be added.

[0023] Moreover, to the dispersion phase, a sensitizer, a viscosityadjusting agent, a solvent, a surfactant for adjusting the surfacetension, or the like may be added in a range not to influence thepolymerization.

[0024] According to the method for preparing resin fine particles of thepresent invention, liquid droplets are formed by discharging a liquidcomprising a polymerizable monomer as a dispersion phase into acontinuous phase; splitting the liquid comprising the polymerizablemonomer by applying mechanical vibration. For example, when liquiddroplets of the polymerizable monomer are discharged into the continuousphase in a condition so as to form a laminar flow from an opening suchas a nozzle or an orifice, a liquid column of the polymerizable monomeris formed in the vicinity of the opening. When a surface wave is appliedto the liquid column by applying the mechanical vibration to the liquidcolumn, the liquid column is deformed so as to generate a constriction,and split from the part to form liquid droplets. The state of the liquiddroplet formation is shown in FIG. 1. Since the constriction part isgenerated according to the vibration frequency, the capacity of onepiece of the liquid droplet can be calculated from the value obtained bydividing the flow amount per unit time by the frequency.

[0025] According to the method for preparing resin fine particles of thepresent invention, a state of the liquid comprising the polymerizablemonomer split into a liquid droplet, that is, the moment of the liquiddroplet formation from the liquid column of the polymerizable monomer,is recognized, and the result is fed back to a condition of thedischarging and/or the mechanical vibration of the liquid comprising thepolymerizable monomer.

[0026] The means for recognizing the state of the liquid dropletsproduced by splitting the liquid is not particularly limited. Forexample, a camera capable of photographing by a high shutter speedsufficient for catching the high speed liquid droplet formation state bya stationary state, a method of combining such a camera and astroboscopic illumination, or the like is preferable. Moreover, in orderto enlarge the minute liquid droplets to a size visibly recognizable, itis preferable to mount an enlarging photography unit to the camera, andit is preferable that the image caught by the camera is indicated on adisplay or the like so as to be recognized easily.

[0027] The feedback refers to the operation of confirming whether or notthe liquid droplets are produced normally as shown in FIG. 1 andadjusting the production condition according to the situation in thecase where abnormality is occurred, or stopping the production dependingon the case. As an example of the abnormality, one shown in FIG. 2 canbe presented. As an example of the feedback in this case, adjustment ismade such that constriction can be generated by enlarging the amplitudeof the mechanical vibration to be applied for splitting the liquiddroplets. By executing the feedback, resin fine particles having ahomogeneous particle size can be produced.

[0028] According to the method for preparing resin fine particles of thepresent invention, resin fine particles can be obtained by polymerizingin a state without splitting or integrating the formed liquid dropletsof the polymerizable monomer. Examples of the method for having theliquid droplets in a state without integration include a method ofadding a dispersion stabilizer to the continuous phase, and the like.Examples of the method for having the liquid droplets in a state withoutsplitting include a method of moderately agitating the continuous phaseso as not to apply excessive mechanical shearing force to the liquiddroplets, and the like. By heating or directing active light in thestate, the polymerizable monomer is polymerized.

[0029] Moreover, resin fine particles of a homogeneous particle size canbe produced also by measuring size of the formed liquid droplets andfeeding back the result to a condition of a discharging and/or amechanical vibration of the liquid comprising a polymerizable monomer.

[0030] According to one aspect of the present invention, provided is amethod for preparing resin fine particles, which comprises discharging aliquid comprising a polymerizable monomer as a dispersion phase into acontinuous phase; splitting the liquid comprising the polymerizablemonomer by applying mechanical vibration to form a liquid droplet; andpolymerizing the liquid droplet in a state without splitting orintegrating the liquid droplet, said method comprising measuring size ofsaid formed liquid droplet, and a condition of said discharging and/orsaid mechanical vibration of the liquid being determined by feedbackfrom a result of the measurement.

[0031] The method for measuring size of the liquid droplets is notparticularly limited, and examples thereof include a method of taking inthe image of the liquid droplets formed in the dispersion phase in acomputer for measurement, and the like. The liquid droplets to bemeasured at the time are not particularly limited as long as they are ina liquid droplet state. Specifically, the image photographed by thecamera can be taken in a computer to measure size of the formed liquiddroplets by image analysis software. A calculation process is executedfor the obtained measurement value for calculating the values of theaverage value, the standard deviation or the like. According to theresult, a feedback operation is executed for adjusting size of theliquid droplets. The feedback can be controlled for example by sending acontrol signal from the computer or via a sequencer to the unit forapplying the mechanical vibration or the unit for adjusting thedischarge of the polymerizable monomer, or the like. For example, in thecase where the particle size is too large, it is adjusted by raising thefrequency of the mechanical vibration or lowering the discharge amountof the polymerizable monomer. In the case where the particle size is toosmall, it is adjusted by executing vice versa.

[0032] According to the method for preparing resin fine particles of thepresent invention, resin fine particles having a very homogeneousparticle size can be obtained. According to one aspect of the presentinvention, provided is a resin fine particle produced by the method forpreparing a resin fine particle according to the present invention,which has an average particle size of 10 to 3,000 μm, and 80% or more ofwhich falls within a range of ±10% of the average particle size.

[0033] Herein, the preferable lower limit of the particle size of theresin fine particles of the present invention is set at 10 μm, and theupper limit is set at 3,000 μm because the resin fine particles havingsuch a particle size can hardly be produced by the suspensionpolymerization, so that the method for preparing resin fine particles ofthe present invention can be particularly effective in this range. Whenthe resin fine particles fallen within the range of ±10% of the averageparticle size are less than 80%, the resin fine particles has aninhomogeneous particle size so that a classification step may be needed.

[0034] It is preferable that a production apparatus for carrying out themethod for preparing resin fine particles according to the presentinvention comprises at least a dispersion container; a jetting opening,opened in the dispersion container, for discharging a liquid comprisinga polymerizable monomer into a liquid dispersion medium; a means forapplying mechanical vibration to the liquid comprising the polymerizablemonomer jetted into the liquid dispersion medium; and a photography unitfor photographing a formed liquid droplet.

[0035] According to one aspect of the present invention, provided issuch a production apparatus for a resin fine particle, which comprises adispersion container; a jetting opening, opened in the dispersioncontainer, for discharging a liquid comprising a polymerizable monomerinto a liquid dispersion medium; a means for applying mechanicalvibration to the liquid comprising the polymerizable monomer jetted intothe liquid dispersion medium; and a photography unit for photographing aformed liquid droplet.

[0036] Although the dispersion container is not particularly limited, inconsideration of photographing the liquid droplet formation state by aCCD camera or the like, and reaction after forming the liquid droplets,a transparent one durable to the heat of about 100° C. is preferable.Examples of the dispersion container include a glass round orcylindrical separable flask container and the like.

[0037] The jetting opening is opened in the dispersion container anddischarges a liquid comprising polymerizable monomer into liquiddispersion medium. As the shape of the opening part of the jettingopening, it is preferably circular, and as the channel shape for theopening, it is preferably cylindrical or truncated conical. As thematerial of the jetting opening, one not to be denaturalized by thecomponent of the dispersion phase and the continuous phase, orchemically influenced. For example, stainless steel, Teflon (Trade Mark)or the like can be presented.

[0038] Although the jetting opening is not particularly limited, it isprovided preferably by one. If a plurality of the jetting openings areprovided side by side, irregularity is occurred in the jetting amountsof the polymerizable monomer from each jetting opening, so that the sizeof the liquid droplets to be formed becomes inhomogeneous by shaking,and furthermore, photographing of a clear image may be difficult due tosuperimposition of the liquid droplets.

[0039] The method for discharging the polymerizable monomer from thejetting opening is not particularly limited, and examples thereofinclude a method of sending a liquid by a pump, and the like. As thepump, one having little pulsation is preferable, and a gear pump havingthe flow amount easily controllable by the rotational frequency can beused preferably. In the case where a plunger pump is used as the pump, arectifying unit needs to be used too. Moreover, it is also possible tosend in compressed air to the monomer container connected with thejetting opening with a pipe for pushing out the monomer from thecontainer, and sending out the same by a constant amount using a flowamount adjusting valve.

[0040] The means for applying the mechanical vibration is notparticularly limited, and examples thereof include: a method ofmechanically vibration by connecting a transducer to a member forsupporting the discharging opening; a method of conveying to the monomeror the dispersion medium the reciprocating motion generated by a pistonconnected with an oscillator for generating an electrical signal havinga regular frequency, and the like. In particular, a method of directlyvibrating the member for supporting the jetting opening is preferable.Examples of the method for generating the mechanical vibration include amethod of generating the vibration using a function generator(electrical signal generator), amplifying the vibration by an amplifier,and supplying the vibration to the transducer, and the like. As thetransducer, one capable of adjusting the frequency and the amplitude bya signal from the outside is preferable.

[0041] Although the photography unit is not particularly limited, a CCDcamera comprising a high speed shutter or a stroboscopic illuminationsufficiently for catching the high speed liquid droplet formation in astationary state, and a display capable of enlarging and displaying theminute liquid droplets in a visibly recognizable size, and the like canbe used preferably.

[0042] According to one aspect of the present invention, provided is aproduction apparatus for a resin fine particle, which comprises adispersion container; a jetting opening, opened in the dispersioncontainer, for discharging a liquid comprising a polymerizable monomerinto a liquid dispersion medium; a means for applying mechanicalvibration to the liquid comprising the polymerizable monomer jetted intothe liquid dispersion medium; and a measuring means for measuring sizeof a formed liquid droplet.

[0043] Although the measuring means for size of the liquid droplets isnot particularly limited, for example, it is preferable to take in theimage obtained by photographing the state of the liquid dropletformation by the photography unit into a computer, and measure size ofthe liquid droplets by an image processing unit.

[0044] Preferably, the production apparatus for the resin fine particleof the present invention further comprises a means for adjusting adischarging condition and/or a mechanical vibration condition of aliquid comprising a polymerizable monomer based on a measurement resultof size of a liquid droplet. Since size of the liquid droplets formed byshaking the monomer jetted into the liquid dispersion medium is directlyproportional to the jetting amount of the polymerizable monomer and itis inversely proportional to the frequency of shaking the polymerizablemonomer, in the case where size of the liquid droplets is too large, anoperation of reducing the discharge amount of the polymerizable monomeror increasing the frequency, and in the case the where size of theliquid droplets is too small, an operation of increasing the dischargeamount of the polymerizable monomer or reducing the frequency isexecuted manually or automatically so as to homogenize size of theliquid droplets.

BEST MODE FOR CARRYING OUT THE INVENTION

[0045] Hereinafter, the present invention will be described in moredetail with reference to examples, however, the present invention is notlimited to these examples.

EXAMPLE 1

[0046] First, a production apparatus for resin fine particles as shownin FIG. 3 was produced.

[0047] In the apparatus shown in FIG. 3, 1 represents a container forliquid polymerizable monomer M, with jetting opening 2 comprising anozzle having a 0.3 mm inner diameter connected with container 1 viapump P opened in liquid dispersion medium D stored in transparentdispersion container 3.

[0048] Monomer M jetted from jetting opening 2 to liquid dispersionmedium D was shaken by transducer 4 connected with a member forsupporting jetting opening 2 so as to produce liquid droplets.Photography unit 5 having {fraction (1/10,000)} seconds high speedshutter and an enlarging lens, which is set for photographing the liquiddroplet splitting state intermittently for every 5 seconds was providedon the right side of dispersion container 3, and illumination unit 6connected with liquid source I for providing a light amount from theback side of liquid dispersion medium D was provided on the left side.

[0049] An image photographed by photography unit 5 was enlarged anddisplayed on 14 inch CRT display 7 via image controller C2, so thatadjustment can be made for homogenizing size of the liquid droplets by amanual operation based on the visual observation result of the state ofsize of the produced liquid droplets. That is, in the case where size ofthe liquid droplets was too large, size of the liquid droplets wasreduced by operating pump controller C1 to reduce the jetting amount ofliquid polymerizable monomer M or by operating function generator(electrical signal generator) FG connected with amplifier A to increasethe frequency of shaking liquid polymerizable monomer M. In the casewhere size of the liquid droplets is too small, in contrast, adjustmentwas made for homogenizing size of the liquid droplets by a manualoperation for enlarging size of the liquid droplets by increasing thejetting amount or reducing the frequency.

[0050] Next, resin fine particles were produced using the apparatus.

[0051] Liquid polymerizable monomer M was produced by mixing 50 parts byweight of divinyl benzene and 50 parts by weight of trimethylol propanetrimethacrylate. With 2 parts by weight of benzoyl peroxide addedthereto, as a polymerization initiator, it was injected into container1.

[0052] Monomer M was jetted into liquid dispersion medium D with 3% ofpolyvinyl alcohol added to water, stored in the glass dispersioncontainer 3 from the jetting opening 2 having a 0.3 mm inner diameter bya 4.96 mL/minute rate. Transducer 4 shook liquid dispersion medium Dwith monomer M jetted by a 200 Hz frequency for producing liquiddroplets.

[0053] Based on the result of the visual observation of the state ofsize of the produced liquid droplets with the image photographed byphotography unit 5 and enlarged and displayed on CRT display 7,adjustment was made for homogenizing size of the liquid droplets by themanual operation.

[0054] By heating and agitating with an agitator and a cooling pipeinstalled in dispersion container 3 after jetting a predetermined amountof monomer M, Monomer M was polymerized so as to obtain resin fineparticles. The average particle size of the obtained resin fineparticles was 602 μm, with 92% of the resin fine particles included in arange of ±10% of the average particle size.

EXAMPLE 2

[0055] A production apparatus for resin fine particles as shown in FIG.4 was produced.

[0056] According to the apparatus shown in FIG. 4, measuring unit S forsize of the liquid droplets was provided on the right side of dispersioncontainer 3. An image photographed by photography unit 5 was sent to themeasuring unit S via image controller C2 so as to measure size of theformed liquid droplets. The result of the calculation process of themeasurement value was fed back to pump controller C1 or functiongenerator (electrical signal generator) FG, so that adjustment is madefor homogenizing the liquid droplet size by an automatic operation.

[0057] Next, resin fine particles were produced using the apparatus.

[0058] In the same manner as in Example 1 except that the apparatusshown in FIG. 4 was used and liquid polymerizable monomer M was preparedusing tetramethylol methane tetra acrylate in place of the trimethylolpropane trimethacrylate, resin fine particles were produced.

[0059] The average particle size of the obtained resin fine particleswas 599 μm, with 89% of the resin fine particles included in a range of±10% of the average particle size.

EXAMPLE 3

[0060] In the same manner as in Example 1 except that the apparatusshown in FIG. 4 was used, resin fine particles were produced. That is,liquid droplets were produced by shaking liquid dispersion medium D withliquid polymerizable monomer M discharged. Size of the produced liquiddroplets were measured by measuring unit S, and the result of thecalculation process of the measured value was fed back to pumpcontroller C1, so that adjustment was made for homogenizing size of theliquid droplets by the automatic operation. By heating and agitatingwith an agitator and a cooling pipe installed in dispersion container 3after jetting a predetermined amount of monomer M, monomer M waspolymerized so as to obtain resin fine particles.

[0061] The average particle size of the obtained resin fine particleswas 601 μm, with 95% of the resin fine particles included in a range of±10% of the average particle size.

COMPARATIVE EXAMPLE 1

[0062] In the same manner as in Example 1 except that the CCD camera andthe CRT monitor were not used, and the discharging condition and thefrequency condition were not adjusted, resin fine particles wereobtained.

[0063] The average particle size of the obtained resin fine particleswas 688 μm, with only 78% of the resin fine particles included in arange of ±10% of the average particle size.

COMPARATIVE EXAMPLE 2

[0064] A resin fine particle production apparatus same as the apparatusused in Example 1 except that three jetting openings 2 each having a 0.3mm inner diameter were opened side by side in liquid dispersion mediumD, was produced.

[0065] Using the apparatus, liquid droplets were produced in the samemanner as in Example 1 except that liquid polymerizable monomer M wasjetted from three jetting openings 2 by a 15.9 mL/minute rate. An imagephotographed by photography unit 5 and enlarged and displayed on CRTdisplay 7 had the liquid droplets superimposed, so that they were notindividually recognized visually.

[0066] The average particle size of the resin fine particles obtained bypolymerizing monomer M without adjustment for homogenizing size of theliquid droplets by a manual operation was 610 μm, with only 65% of theresin fine particles included in a range of ±10% of the average particlesize.

Industrial Applicability

[0067] According to the present invention, it is possible to provide amethod for preparing resin fine particles of a homogeneous particle sizeused in the fields of chemistry, medicine, electronic material or thelike, resin fine particles and a production apparatus for resin fineparticles.

1. A method for preparing a resin fine particle, which comprisesdischarging a liquid comprising a polymerizable monomer as a dispersionphase into a continuous phase; splitting the liquid comprising thepolymerizable monomer by applying mechanical vibration to form a liquiddroplet; and polymerizing the liquid droplet in a state withoutsplitting or integrating the liquid droplet, said method comprisingrecognizing a moment of a liquid droplet formation from a liquid columnof said polymerizable monomer, and a condition of said dischargingand/or said mechanical vibration of the liquid being determined byfeedback from a result of the recognition.
 2. A method for preparing aresin fine particle, which comprises discharging a liquid comprising apolymerizable monomer as a dispersion phase into a continuous phase;splitting the liquid comprising the polymerizable monomer by applyingmechanical vibration to form a liquid droplet; and polymerizing theliquid droplet in a state without splitting or integrating the liquiddroplet, said method comprising measuring size of said formed liquiddroplet, and a condition of said discharging and/or said mechanicalvibration of the liquid being determined by feedback from a result ofthe measurement.
 3. A resin fine particle produced by the method forpreparing a resin fine particle according to claim 1, which has anaverage particle size of 10 to 3,000 μm, and 80% or more of which fallswithin a range of ±10% of the average particle size.
 4. A apparatus forcarrying out the method for preparing the resin fine particle accordingto claim 2, which comprises a dispersion container; a jetting opening,opened in the dispersion container, for discharging a liquid comprisinga polymerizable monomer into a liquid dispersion medium; a means forapplying mechanical vibration to the liquid comprising the polymerizablemonomer jetted into the liquid dispersion medium; and a photography unitfor photographing a formed liquid droplet.
 5. A apparatus for carryingout the method for preparing the resin fine particle according to claim2, which comprises a dispersion container; a jetting opening, opened inthe dispersion container, for discharging a liquid comprising apolymerizable monomer into a liquid dispersion medium; a means forapplying mechanical vibration to the liquid comprising the polymerizablemonomer jetted into the liquid dispersion medium; and a measuring meansfor measuring size of a formed liquid droplet.
 6. A apparatus forcarrying out the method for preparing the resin fine particle accordingto claim 2, which comprises a dispersion container; a jetting opening,opened in the dispersion container, for discharging a liquid comprisinga polymerizable monomer into liquid dispersion medium; a means forapplying mechanical vibration to the liquid comprising the polymerizablemonomer jetted into the liquid dispersion medium; a measuring means formeasuring size of a formed liquid droplet and, a means for adjusting adischarging condition and/or a mechanical vibration condition of aliquid comprising a polymerizable monomer based on a measurement resultof size of a liquid droplet.
 7. A resin fine particle produced by themethod for preparing a resin fine particle according to claim 2, whichhas an average particle size of 10 to 3,000 μm, and 80% or more of whichfalls within a range of ±10% of the average particle size.